Why is 1 million milligrams 1 kilogram

Lets write it down
1000000 MG
now lets convert 1 million MGs to grams. every gram is 1000 miligram so we need to devide our original number by 1000 to convert it into grams
1000000÷1000=1000
so 1 million MG is 1000 gram
now lets convert grams to kilograms.
a kilogram is 1000 grams so we need to devide 1000 grams by 1000 to convert it into kilograms
1000g÷1000=1kg
there you go 1 million milligram is 1 kilogram.
so by what we learned from here. we can bypass this long procces and just devide by 1 million if we want to convert milligrams to kilograms(since 1 million milligrams is 1 kilogram)

Something that is true about that is that it has numbers